Although it is difficult to decipher the North's latest contradictory foreign policy, analysts believe the move may be part of an internal power game between hawks and doves in the North Korean regime under new leader Kim Jong-un.
North Korea's Committee for the Peaceful Reunification of the Fatherland, a key party organ in charge of South Korean affairs, also stepped up its campaign against presidential hopefuls in Seoul in what appeared to be a move to influence the December presidential election.
Early this week, the North's committee threatened to reveal detailed remarks by three South Korean presidential hopefuls, including a leading contender, Park Geun-hye, when they each visited Pyongyang.
Baek Seung-joo, a senior analyst at the state-run Korea Institute for Defense Analyses in Seoul, said the motive behind the North Korean committee to attack South Korean presidential hopefuls may be "aimed at protecting pro-North Korean forces in South Korea and influencing the presidential election."
Relations between the two Koreas worsened seriously after President Lee Myung-bak, whose term ends next February, took office in early 2008, as North Korea protested strongly against his policy of linking aid to progress in international efforts to end Pyongyang's nuclear weapons programs.
In the North Korean committee's perspective, Baek said the latest ploy is aimed at "showing off its presence in an internal power game in North Korea."
The North's new leader, Kim Jong-un, took over the communist nation after his father and longtime ruler, Kim Jong-il, died last December. Since then, Pyongyang has sent mixed signals to the world.
Weeks before the failed rocket launch, North Korea and the U.S. announced an agreement in which Washington would resume food aid to the impoverished nation in return for the suspension of missile and nuclear tests.
In the newest verbal threat on June 4, North Korea's military vowed to wage a "sacred war" against major South Korean media organizations for insulting its top leader, underlining the seriousness of its intentions by revealing the map coordinates of their respective headquarters in Seoul.
"There is a fierce competition to grab a leading role in South Korea policy between the North Korean military and the Unification Front Line Department (which has the Committee for the Peaceful Reunification of the Fatherland under its wing)," Baek said.
North Korea's military leaders have stuck to its policy of provocations against South Korea to keep their "vested rights" and check the power of Jang Song-thaek, the uncle of Kim Jong-un, who is believed to be in his late 20s, Baek said.
In a seeming departure from the aggressive policy toward South Korea, the North's foreign ministry said last week it has no plan to carry out a nuclear test "at present."
The North's ministry, however, accused South Korea of trying to "rattle the nerves of the DPRK (North Korea) in a bid to cause it to conduct a nuclear test."
Yang Moo-jin, a professor at the University of North Korean Studies, said, "The North Korean foreign ministry's statement was aimed at the U.S."
"The announcement that North Korea has no plan to conduct a nuclear test can be interpreted as pressing the U.S. to hold talks," Yang said.
A North Korean expert, who spoke on the condition of anonymity, considered the North's contradictory foreign policy to be evidence that Kim Jong-un is not fully in power yet.
"Until Kim Jong-un secures a solid power base in both the ruling party and the military, North Korea's foreign policy is unlikely to make its direction clear," the expert said.